The present invention relates to the field of air data probes and more particularly to a new and improved air data probe system and method to be used simultaneously to map real time atmospheric conditions and to detect the presence, thickness, and continued buildup of ice on the exterior surface of an aircraft. Sensing air data information such as forward air pressure, ambient air pressure, temperature, and humidity is known, and an example of such sensing devices is illustrated in U.S. Pat. No. 5,616,861. Additionally, U.S. Pat. No. 5,359,888 discloses an air data probe for measuring air turbulence and wind shear. Typically these probes are positioned on the surface of the fuselage of an airplane to measure local airflow conditions. This information is then relayed to the pilot to inform the pilot of the current flying conditions.
Several devices for optical ice detection have been previously disclosed. One such device incorporates a sensor at one end of an optical channel comprised of a fiber optic bundle. The fiber optic bundle totally reflects light internally when no ice is present, but when water or ice is present, some of the incident light is refracted externally. Another device attempts to detect ice and ice depth by using two or more optical fibers to transmit light and receive reflected light. The device relies on reflections from the surface at the ice/air interface to assess the presence and depth of ice. Other devices use single optical fibers to detect the presence of ice through the scattering or reflection of light at the end of the optical fiber. These devices suffer from serious technical limitations due to roughness of the ice surface and imperfections in the ice""s scattering of the light.
The present invention generally relates to an integrated air data probe capable of remotely sensing in-flight meteorological conditions. A ground-based network would then have the ability to independently monitor lower and upper atmospheric weather and environmental conditions and thus more accurately map, forecast, and relay those conditions to other aircraft and to ground applications. A very large number of aircraft can be equipped with the air data probe, which will permit the sampling of atmospheric conditions from a large pool of data points. Such a system can provide atmospheric information that is either not available or very limited through present technologies such as ground stations, satellites, or weather balloons. The data from these probes can be transmitted to a network of ground stations for analysis, for use in modeling, and for construction of a real time map of the present flying and atmospheric conditions. Because of the large number of integrated data probes, this data will lead to improve meteorological modeling and weather forecasting. Additionally, this information can be used to create a real time map of where actual icing and significant turbulence exists. This map can then be transmitted to aircraft for use in planning optimum flight altitudes and headings, promoting safety and comfort, and reducing flight times and fuel consumption. Although the present invention is particularly useful in planning the flights of other aircraft, it should be appreciated that the invention is also useful in ground activity which requires prediction of weather, such as planning recreational events, alerting emergency personal, etc.
In a preferred form of the invention, an airfoil shaped probe is attached to the external surface of an airplane such as the wing, fuselage, or empannage and is adapted to measure various conditions and relay the measurements to a receiving station. The probe may, for example, measure airspeed, pressure altitude functions, temperature, humidity, static air temperature, relative air humidity, heading, turbulence, and ice build-up. With the exception of ice build-up, these measurements are achieved and collected by conventional devices. Dew point may also be calculated using the temperature, pressure, and humidity data. Additionally, when probe data is combined with aircraft position data, such as GPS data, winds aloft can be calculated.
With respect to ice detection, the probe includes a recessed surface, and by positioning the recessed surface directly into the airflow, the probe detects the presence, thickness, and continued buildup of ice. One or more light beams are passed over and substantially parallel to the recessed surface, and as ice develops on the recessed surface, ice will obstruct the beam detector, such that the beam will no longer be detectable by the beam detector. Preferably, the intensity of the detected beam will fall below a threshold detectable intensity of light and will effectively not be detected, or the detected intensity will be below a selected intensity value, that will be interpreted as being caused by the presence of ice. For best results, the recessed surface faces directly into the airflow, preferably in the laminar flow. The length of the recessed surface is set to optimize the system for the specific application involved. The beams can be of any appropriate wavelength, however, for best results, visible, infrared, or ultraviolet beams should be used.
If two or more beams are used, then each beam emitter may be paired with a beam detector and the corresponding beam detector detects only the beam from that emitter. This can be accomplished by numerous methods. For example, by powering each prescribed beam emitter alternately and sampling the output of the corresponding detector, by electronically modulating the beam from a single emitter to a specific frequency with corresponding detectors designed to respond to the specific frequency, or by using an optical filter that passes only a specific range of wavelengths. The invention also may utilize an optical filter placed in front of the detector to filter out ambient light, may utilize redundant temperature sensors to measure the temperature of the probe, and may utilize a probe heater to melt accumulated ice to assess continued ice accumulation.
There has thus been outlined features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth above or in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.